Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Blood Culture Isolates from Three Hospitals in Turkey

We aimed to investigate the clonal relationships, common sequence types, and carbapenemase genes in 177 non-repetitive blood culture isolates of Acinetobacter baumannii collected from patients at three university hospitals in Turkey in 2016. Molecular epidemiological characteristics of the isolates were examined using pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) (Pasteur scheme-cpn60, fusA, gltA, pyrG, recA, rplB, and rpoB). Multiplex PCR was used to investigate the carbapenemase genes, including bla(OXA-23-like),bla(OXA-24-like), bla(OXA-48-like), bla(OXA-58-like), bla(IMP), bla(VIM) and bla(NDm). PFGE genotyping yielded 92 pulsotypes with a clustering ratio of 69.7%. As per a >= 85% similarity coefficient, 159 (90.9%) isolates were found to be clonally related. The bla(OXA-)(23-like) and bla(OXA-)(58)-like genes were identified in 100% and 28.2% of the isolates, respectively. The bla(NDM) gene was identified in two isolates. The MLST analysis included 54 isolates with different pulsotypes, and 29 sequence types (STs). Most of the isolates (n = 36) belonged to the clonal complex (CC)2, one isolate belonged to CC1, and one isolate belonged to CC164. Sixteen new STs (ST1235-ST1250) were identified. Identifying both global ST2 and a large number of new STs, revealed high genetic diversity in A. baumannii isolates in the study population.